CN103137439B - A kind of recovery method of GaN base epitaxial wafer substrate - Google Patents

Abstract

The invention discloses a method for recycling a GaN-based epitaxial wafer substrate, which belongs to the technical field of semiconductors. The method includes: putting GaN-based epitaxial wafers into a vacuum reaction chamber; introducing reducing gas and catalytic gas into the reaction chamber, so that the GaN of the GaN-based epitaxial wafers undergoes a reduction reaction under vacuum. In the present invention, the GaN-based epitaxial wafer is put into a vacuum reaction chamber, and the reducing gas and catalytic gas are introduced into the reaction chamber, so that the GaN of the GaN-based epitaxial wafer undergoes a reduction reaction, and the GaN of the GaN-based epitaxial wafer is reduced into a simple substance. gallium and ammonia, thereby separating from the substrate. This method has no physical and chemical damage to the substrate material in a high-temperature environment, and maintains the integrity of the substrate. The principle of the method is simple, the process is controllable, and the decomposition rate of GaN can be increased, thereby improving the recovery of the substrate. speed.

Description

A kind of recovery method of GaN-based epitaxial wafer substrate

technical field

The invention relates to the technical field of semiconductors, in particular to a method for recycling GaN-based epitaxial wafer substrates.

Background technique

With the rapid development of optoelectronic industries such as light-emitting diodes and photodetectors, the production capacity of GaN-based epitaxial wafers based on substrates such as aluminum oxide or silicon carbide has increased unprecedentedly. When growing GaN-based epitaxial wafers, the appearance or photoelectric parameters of some epitaxial wafers cannot meet the requirements of subsequent production, and they need to be scrapped or downgraded. Since the substrate material accounts for a considerable proportion in the cost of epitaxial wafers, the industry is emerging to recycle the substrates of scrapped epitaxial wafers.

Traditional GaN-based epitaxial wafer substrate recovery methods generally include dry etching and wet etching. The dry etching method generally uses chlorine gas, a strong oxidizing gas that can react with GaN, to physically and chemically etch GaN under a certain pressure, gas flow rate and plasma environment. The wet etching method generally uses a hot alkaline solution to etch GaN.

In the process of realizing the present invention, the inventor finds that there are at least the following problems in the prior art:

In the prior art, when the substrate of GaN-based epitaxial wafers is recovered by dry etching, due to the plasma bias, certain damages will be formed on the substrate of the epitaxial wafers; the recovery of GaN-based epitaxial wafers by wet etching method When the substrate is used, because the GaN of the epitaxial wafer is relatively stable, it is difficult to obtain a high etching rate by wet etching, which makes it difficult to increase the productivity of removing GaN and recovering the substrate.

Contents of the invention

In order to solve the problems in the prior art, an embodiment of the present invention provides a GaN-based epitaxial wafer substrate recycling method. Described technical scheme is as follows:

An embodiment of the present invention provides a method for recycling a GaN-based epitaxial wafer substrate, the method comprising:

Put the GaN-based epitaxial wafer into a vacuum reaction chamber, the GaN-based epitaxial wafer includes a substrate, and an n-type GaN layer, a multi-quantum well layer and a p-type GaN layer stacked on the substrate in sequence, the substrate Al2O3 substrate or silicon carbide substrate;

Introducing a reducing gas and a catalytic gas into the reaction chamber, so that the GaN of the GaN-based epitaxial wafer undergoes a reduction reaction under vacuum, the reducing gas is hydrogen, the catalytic gas is hydrogen chloride gas, and the reduction reaction The product is elemental gallium and ammonia;

When hydrogen chloride gas and hydrogen gas are introduced into the reaction chamber, according to the following reduction reaction, GaN on the GaN-based epitaxial wafer is decomposed into elemental gallium and ammonia gas at a high temperature of 900°C to 1100°C under the action of hydrogen chloride gas and hydrogen gas :

GaN+HCl↑+H ₂ ↑→NH ₃ ↑+GaCl↑;

2GaCl+H2↑→2HCl+2Ga;

In the above reaction, hydrogen chloride gas is the catalytic gas, and the elemental gallium produced by the reaction is detached from the epitaxial wafer in solid form and deposited in the reaction chamber.

Preferably, when introducing a reducing gas and a catalytic gas into the reaction chamber so that the GaN of the GaN-based epitaxial wafer undergoes a reduction reaction under vacuum, the method further includes:

A vacuum pump is used to pump out the gas in the reaction chamber.

Preferably, the method also includes:

Collect the gas pumped out by the vacuum pump.

The beneficial effects brought by the technical solution provided by the embodiments of the present invention are:

By putting the GaN-based epitaxial wafer into a vacuum reaction chamber, introducing reducing gas and catalytic gas into the reaction chamber, so that the GaN of the GaN-based epitaxial wafer undergoes a reduction reaction, and the GaN of the GaN-based epitaxial wafer is reduced to simple gallium and ammonia gas, thereby separating from the substrate. This method has no physical and chemical damage to the substrate material in a high-temperature environment, and maintains the integrity of the substrate. The principle of the method is simple, the process is controllable, and the decomposition rate of GaN can be increased, thereby improving the recovery of the substrate. speed.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings that need to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained based on these drawings without creative effort.

Fig. 1 is a flowchart of a recycling method for a GaN-based epitaxial wafer substrate provided by an embodiment of the present invention.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the implementation manner of the present invention will be further described in detail below in conjunction with the accompanying drawings.

Example

An embodiment of the present invention provides a method for recycling a GaN-based epitaxial wafer substrate, as shown in FIG. 1 , the method includes:

Step 101: Put the GaN-based epitaxial wafer into a vacuum reaction chamber.

Specifically, a GaN-based epitaxial wafer generally includes a substrate, and an n-type GaN layer, a multi-quantum well layer and a p-type GaN layer sequentially stacked on the substrate.

Specifically, the substrate may be an aluminum oxide substrate or a silicon carbide substrate.

Step 102: Feed reducing gas and catalytic gas into the reaction chamber, so that the GaN on the GaN-based epitaxial wafer undergoes a reduction reaction under vacuum.

Specifically, in this embodiment, the reducing gas may be hydrogen.

Specifically, in this embodiment, the catalytic gas may be hydrogen chloride gas.

Specifically, the reaction temperature of the reduction reaction is 900°C to 1100°C.

Specifically, when hydrogen chloride gas and hydrogen gas are introduced into the reaction chamber, GaN on the GaN-based epitaxial wafer will be decomposed into simple substances at a high temperature of 900°C to 1100°C under the action of hydrogen chloride gas and hydrogen gas according to the following reduction reaction Gallium and Ammonia:

GaN+HCl↑+H ₂ ↑→NH ₃ ↑+GaCl↑(1)

2GaCl+H2↑→2HCl+2Ga(2)

Above-mentioned reaction equation (1) and (2) can be reduced to the reaction formula (3) of following formula:

2GaN+3H2↑→2NH3↑+2Ga(3)

Specifically, in the above reaction, hydrogen chloride gas is the catalytic gas. And the elemental gallium produced by the reaction is detached from the epitaxial wafer in solid form and deposited in the reaction chamber, so that it can be recycled easily. By using hydrogen to reduce GaN into elemental gallium and ammonia, the generated elemental gallium and ammonia will detach from the substrate, thereby obtaining a complete substrate.

Preferably, when introducing a reducing gas and a catalytic gas into the reaction chamber so that the GaN of the GaN-based epitaxial wafer undergoes a reduction reaction under vacuum, the method further includes:

A vacuum pump is used to pump out the gas in the reaction chamber. The ammonia gas produced by the reaction can be pumped out by setting a vacuum pump.

Further, the method also includes:

Collect the gas pumped by the vacuum pump.

Specifically, the ammonia gas pumped out by the vacuum pump can be collected to recycle the reaction product.

Specifically, this embodiment provides a method for recovering the substrate. In practice, the decomposition rate of GaN on GaN-based epitaxial wafers can be improved by optimizing the vacuum degree of the reaction chamber and/or the flow rate of the gas introduced, thereby increasing the substrate recovery rate. bottom recovery speed.

The beneficial effects brought by the technical solution provided by the embodiments of the present invention are:

By putting the GaN-based epitaxial wafer into a vacuum reaction chamber, introducing reducing gas and catalytic gas into the reaction chamber, so that the GaN of the GaN-based epitaxial wafer undergoes a reduction reaction, and the GaN of the GaN-based epitaxial wafer is reduced to simple gallium and ammonia gas, thereby separating from the substrate. This method has no physical and chemical damage to the substrate material in a high-temperature environment, and maintains the integrity of the substrate. The principle of the method is simple, the process is controllable, and the decomposition rate of GaN can be increased, thereby improving the recovery of the substrate. speed.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. within range.

Claims (3)

1. a recovery method for GaN base epitaxial wafer substrate, is characterized in that, described method comprises:

GaN base epitaxial wafer is put into the reaction chamber of vacuum, described GaN base epitaxial wafer comprises substrate and is sequentially laminated on n-type GaN layer, multiple quantum well layer and the p-type GaN layer on substrate, and described substrate is alundum (Al2O3) substrate or silicon carbide substrates;

Reducing gas and catalytic gas is passed in described reaction chamber, reduction reaction is there is under vacuo to make the GaN of described GaN base epitaxial wafer, described reducing gas is hydrogen, and described catalytic gas is hydrogen chloride gas, and the product of described reduction reaction is Metallic Gallium and ammonia;

When passing into hydrogen chloride gas and hydrogen in reaction chamber, according to following reduction reaction, the GaN of GaN base epitaxial wafer, under the effect of hydrogen chloride gas and hydrogen, under the high temperature of 900 DEG C ~ 1100 DEG C, is decomposed into Metallic Gallium and ammonia:

GaN+HCl↑+H ₂↑→NH ₃↑+GaCl↑；

2GaCl+H2↑→2HCl+2Ga；

In above-mentioned reaction, hydrogen chloride gas is catalytic gas, and the Metallic Gallium that reaction generates departs from epitaxial wafer in solid form and is deposited in reaction chamber.

2. method according to claim 1, is characterized in that, passing into reducing gas and catalytic gas in described reaction chamber, when there is reduction reaction under vacuo to make the GaN of described GaN base epitaxial wafer, described method also comprises:

Vacuum pump is adopted to be pumped by the gas in described reaction chamber.

3. method according to claim 2, is characterized in that, described method also comprises:

Collect the gas that described vacuum pump pumps.